Best zoom compared to prime lenses

I currently have the zeiss 24mm 1.8 for my nex 7, and I love it but not having a zoom doesn't suit my shooting style. I alsohave an la-ea2. Besides the 1.8 aperture,whashould I be giving up by selling the 1.8 24mm and getting a zeiss alpha 2.8 24-70? I know the lens is bigger and heavier, but would I be giving up much in pure pq and sharpness? Can this lens compete with my prime?